Flexible CO2 laser system for fundamental research related to an extreme ultraviolet lithography source.

A CO(2) laser system with flexible parameters was developed for fundamental research related to an extreme ultraviolet (EUV) lithography source. The laser is a master oscillator and power amplifier (MOPA) system, consisting of a master oscillator, an externally triggered plasma switch, a preamplifier, a main amplifier, and electronic synchronization units. The laser pulse duration can be varied easily from 10 to 110 ns, with a constant peak power for pulse durations from 25 to 110 ns. The MOPA laser system can also be operated in dual-oscillator mode to produce laser pulse with pulse duration as long as 200 ns and a train of laser pulses with flexible interval. The divergence of the laser beam is 1.3 times the diffraction limit. The laser intensity on the target surface can be up to 8x10(10) W/cm(2). Utilizing this CO(2) MOPA laser system, high conversion efficiency from laser to in-band (2% bandwidth) 13.5 nm EUV emission has been demonstrated over a wide range of laser pulse durations.

Trabeculectomy with intraoperative mitomycin C versus 5-fluorouracil. Prospective randomized clinical trial.

OBJECTIVE: To evaluate the relative efficacy and safety of 5-fluorouracil (5-FU) and mitomycin C (MMC) when used as adjuncts with primary trabeculectomy in eyes not at high risk for failure. DESIGN: Prospective multicenter, randomized clinical trial. PARTICIPANTS: One hundred thirteen patients with primary open-angle, pseudoexfoliative, pigmentary, or angle-closure glaucoma undergoing primary trabeculectomy were recruited. METHODS: One eye of each patient was randomized to receive either 5-FU (50 mg/ml for 5 minutes) or MMC (0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), visual acuity, complications, and interventions were documented at fixed intervals after surgery. The study also examined progression of visual field loss, long-term complications, and bleb appearance 3 years after surgery. RESULTS: Of the 108 patients with complete perioperative information, 54 eyes received 5-FU and 54 received MMC. The proportion of patients reaching different predefined target IOPs after surgery was slightly higher in the MMC group than in the 5-FU group. This difference was less than 25%, which would have been necessary to achieve statistical significance with a power of 0.8 and the sample size used. Likewise, there was no statistically significant difference between the groups with regard to mean preoperative IOP, complications, or interventions. Mean postoperative follow-up was 309 and 330 days in the 5-FU and MMC groups, respectively (P = 0.593). CONCLUSIONS: 5-Fluorouracil and MMC were found to be equally safe and effective adjuncts to primary trabeculectomy in the short- and medium-term postoperative periods.

Hypertension and its determinants among primary-school children in Kuwait: an epidemiological study.

A multistage, stratified random sample of 1312 students (aged 6-10 years) was selected from the five regions in Kuwait. Parents were interviewed and weight, height and urine analysis of the children were taken. Blood pressure was measured on at least three separate occasions. The overall prevalence of hypertension (average systolic and/or diastolic blood pressure > 95th percentile for age and sex) was 5.1%. In multivariate logistic regression analysis, certain groups of Kuwaiti schoolchildren were much more likely to develop hypertension. They included children whose parents were consanguineous, children with a family history of hypertension and obese children.

Arsenate resistance as a possible marker in the differentiation of environmental and clinical isolates of Vibrio parahaemolyticus.

Strains of Vibrio parahaemolyticus were isolated from clinical, marine and freshwater fish of Calcutta, West Bengal, India. Drug and metal resistance characteristics were compared for differentiation of clinical and environmental strains. Eighteen out of the twenty environmental isolates were resistant to arsenate, unlike the clinical isolates which were all susceptible. All the thirty-five isolates of V. parahaemolyticus were resistant to ampicillin and streptomycin.

Significance of the secreted form of IpaC, a 45 kDa protein of Shigella dysenteriae 1, in the invasive process as determined by monoclonal antibodies.

Invasion plasmid antigen C (IpaC), a 45 kDa plasmid encoded protein, is associated with the virulence of virulent Shigella spp. In S. dysenteriae type 1 the 45 kDa IpaC protein is secreted to a greater extent into the surrounding medium in comparison to other Shigella spp. Monoclonal antibodies (mAbs) to the secreted form of IpaC protein were raised in this study. Of the four secretory hybrid cells, one (3G4) was found to have a very high antibody titre as determined by ELISA. The specificity of 3G4 was confirmed by immunoblotting of whole cell extract of Escherichia coli strain MC1061 carrying the plasmid pHW756 which synthesizes both the IpaB and C proteins. The effect of the mAbs on plaque formation by virulent Shigella dysenteriae 1 was determined and it was found that the clone 3G4 substantially (55%) reduced plaque formation on HeLa cell monolayer. The epitope specificity of the mAb 3G4 was competitively inhibited by the convalescent phase sera from human, suggesting that the epitope recognized by clone 3G4 was expressed during the natural course of infection and also indicating that the 45 kDa (IpaC) protein in secreted form has a definite role in the invasive process.

Subcellular localization of IpaC, an invasion plasmid antigen of Shigella dysenteriae type 1 and its in-vitro binding capability to mammalian cells.

Invasion plasmid antigen C (IpaC), a 45-kDa protein encoded by an invasion plasmid of Shigella, is associated with the invasion of epithelial cells by the bacteria. Invasive strains of S. dysenteriae type 1 secreted more proteins into the extracellular environment than a non-invasive strain and secreted more IpaC protein. An anti-IpaC mouse monoclonal antibody was used as a probe to determine the subcellular localization of IpaC and its involvement in invasion of mammalian cells. Immunogold labelling of ultrathin sections of invasive bacteria indicated that the IpaC was only present in the cytoplasmic membrane and cytoplasm. There were no gold-IgG particles on the bacterial surface. Immunoblot analysis of different cellular fractions confirmed that the protein was associated with the inner cytoplasmic membrane and cytosolic fraction. The in-vitro binding capability of the IpaC protein was assessed using HeLa and isolated rat intestinal epithelial cells. The binding of the protein to the surface of mammalian cells indicates that it may have a role in the early stages of the infection process. The binding was sensitive to the action of proteolytic enzymes.

Comparative study of repair of incisional hernia.

Repair of incisional hernias was compared with four different techniques in 55 patients to determine the best method of repair with least chance of recurrence. The maximum incidence of incisional hernia was seen in 30-39 years age group and was most frequently seen after gynaecological surgery (37 cases). Forty eight (88%) patients were operated in emergency by trainee surgeons. Most hernias occurred within one year after surgery and the herniation of lower mid line incision was more frequent (70.9% cases). History of wound infection of previous surgery was recorded in 45.5% of cases which appeared to be the important risk factor in causation of incisional hernia. It was also observed that simple repair of incisional hernia was associated with a high recurrence than that where synthetic mesh was used in repair where no recurrence was recorded.

A 4-kilobase congo red binding plasmid DNA fragment of Shigella dysenteriae 1 suppresses the growth and cell differentiation in Escherichia coli.

A 4-kilobase congo red binding plasmid DNA fragment of pCAT 120 of Shigella dysenteriae 1 was transferred to an Escherichia coli K12 strain by transformation. Transformants were unable to grow in any liquid broth medium. Electron microscopic studies revealed that the transformants grown on tryptic soy agar were associated in clusters after cell division. Normal cell separation among the transformants in comparison with recipient E. coli K12 was only observed when the growth medium was supplemented with sterile culture filtrate of the recipient strain. An unknown factor(s) required for cell separation located on the chromosome was suppressed by a 4-kb congo red binding plasmid DNA (pCAT 120) fragment of S. dysenteriae 1.

Role of a large plasmid of Salmonella typhi encoding multiple drug resistance.

Twenty isolates of Salmonella typhi from cases of typhoid during the 1989-1990 epidemic in Calcutta were examined. Most isolates (84% of all isolates in the epidemic) were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin but were sensitive to nalidixic acid and ciprofloxacin. Plasmids of 120 kb and 14 kb were identified amongst the multi-drug resistant isolates of S. typhi. However, there was no plasmid in the antibiotic-sensitive isolates. The 120-kb plasmid was transferable and transconjugants were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin. Restriction endonuclease analysis patterns after EcoRI digestion of the 120-kb antibiotic-resistance plasmids from the S. typhi isolates and transconjugants were similar.